VB if-statement in PHP - php

Question

I need help to convert the following Visual Basic statement into a PHP equivalent:
If Not IsNumeric(siteid) Then
dr = GetDataReader("SELECT siteid FROM nwsite WITH (NOLOCK) WHERE mac_address = '" & siteid & "'")
If Not dr.HasRows Then
Response.Write(sep & siteid & "=" & siteid)
sep = ","
End If
If Not dr Is Nothing Then
dr.Close()
End If
End If
I need help with the If statements more than anything.
Thanks

Answer 1

See here for the docs you need to check, also here
Seems like you also need to learn how to use mySQL in PHP
The code is relatively easy, in its simplest step- almost line for line from what you have to help you see the transformation to PHP (there are better implementations):
$siteid = 1; // where 1 is the value of siteid, PHP vars are prefixed with '$'
// you also could do
// if(!isset($siteid){
// if(!$siteid){
if(!is_numeric($siteid){
// there is no site ID, so get it from the DB
// Make a MySQL Connection
mysql_connect("localhost", "user", "password") or die(mysql_error());
mysql_select_db("dbname") or die(mysql_error());
// Run your query
$result = mysql_query("SELECT siteid FROM nwsite WITH (NOLOCK) WHERE mac_address = ".$siteid)
or die(mysql_error());
if(mysql_num_rows($result)>0){
// rows returned
//assuming only one row is returned, with your siteid value
$row = mysql_fetch_array( $result );
$siteid=$row['siteid'];
}else{
// no rows returned
// do something
}
}else{
// $siteid is already a valid value
}

Answer 2

AN if statement goes something like this:
if(someexpression){
$yourcode = "your things";
}
quick mockup of your code:
if(!is_numeric($siteid){
//sql call
$result = yourdb->query('SELECT');
if(!$result){
echo "error";
}
}

Answer 3

if(!$this->IsNumeric($siteid))
{
$dr = $this->GetDataReader("SELECT siteid FROM nwsite WITH (NOLOCK) WHERE mac_address = $siteid");
if(!$dr->hasRows())
{
echo "$sep$siteid = $siteid";
$sep = " , ";
}
if(!is_null($dr))
{
$dr->close();
}
}

Answer 4

Following code may help you:
if (!is_numeric($siteid)) {
$res = mysql_query("SELECT siteid FROM nwsite WHERE mac_address = " . mysql_real_escape_string($siteid));
$rows = mysql_fetch_assoc($res);
if (count($rows) == 0) {
print($sep . $siteid . "=" . $siteid);
$sep = ',';
}
}